Interlocking system for railroads



Aug. 7, 1934. s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed July 31, 1931 Patented Aug. 7, 1934 1,969,053 INTERLOCKING SYSTEM FOR RAILROADS Sedgwick N. Wight, Rochester, Y assignor to General Railway Signal companyrltochester,

Application July 31, 1931, Serial No.' 554,24l

' 9 Claims. (01. 243-3 This invention relates to interlocking systems, and more particularly tointerlocking systems of the free-lever type.

It has been the practice to provide mechanical 5 interlocking between levers, and in many cases electrically locked levers, in interlocking plants for railway systems to afford the necessary protection against setting up conflicting train moves in the railway yard. If electrical or mechanical locking of levers is employed, the levers must of necessity be rather large and the locking mechanism must be comparatively strong, which of course not only makes the lever or control machine cumbersome but also expensive, whereas,

' on the other hand, free levers may be very small and the entire control machine be made very compact, so that in the smaller plants all levers can be reached by a single man sitting at a desk.

Since a certain amount of time must elapsebetween the movement of, a switch machine lever and the response of the switch machine to such change oflever position, it is considered expedient not to allow the clearing of a signal associated with such switch machine while the switch machine is out of correspondence with its control 18- ver, since otherwise a signal might be cleared for the route present before the switch machine has actually started to move. If, on the other hand, the signal can only be clear with the switch machine lever in correspondence with the switch machine it controls, it would of course be possible to put the signal to stop by moving the switch machine lever, and this is also very undesirable. In view of theforegoing and other important considerations, it is proposed in accordance with the present invention to employ a correspondence relay which can only be picked up if the switch machine lever is in correspondence with the switch machine it controls, and to so organize the circuits that the associated signal cannot be cleared unless the correspondence relay is energized together with means for cancelling the requirement of correspondence of the associated switch machine-and its control lever, upon clearing of the signal, so that thereafter movement of the switch machine lever will not put the signal to stop.

Other objects, purposes and characteristic features of the present invention will in part be obvious from the accompanying drawing and will in part be more specifically pointed out hereinafter. In describing one specific embodiment of the invention in detail reference will be made to the accompanying drawing illustrating one embodiment of the invention.

Referring to the accompanying drawing, the rails 3 of the main track of a railway system have been shown divided intotraclrsections by insulating joints 4, 0! which the detector track section including the track relay T and the track battery 5 only have been shown in detail. From this main track diverges a siding or diverging route having track rails 6 insulated from the detectortrack circuit by insulating joints '7, through the medium of a track switch S, preferably powerroperated as by a switch machine SM. At theentrance to this passing siding has been shown a main signal 1 and a diverging route signal 2. Although these signals 1 and 2 have been conventionally illustrated as semaphore signals they may be light signals of any suitable construction, well known in the art. As already pointed out the presentinvention relates principally-to the interconnected control of the switch machine and signals 1 and 2,'aII1d one particular circuit ar rangement for carrying out the control in accordance with this invention will now be specifically described.

The home relay H signifies any suitable relay controlled in accordance with tr'affic conditions in advance, and as illustratedamong other things,

is controlled, by front contacts 8 and 9 of track relays '1" and T respectively, The-lock role-XL is a relay which is intended to prevent operation of the switch machine SM when it is unsafe to move the switch S, and this relay L is preferably controlled in theiollowing manner. The lock relay L is'a sticlcrelay having "two pick-11p circuits and one stick'circuit. The two pick-up cir cuits for relayjL' may be traced as follows':('l) beginning at plusLi-H, front contact 16 of track relay T, normally open contact 1? ct thermal re.-

lay TR, wire .18, windi s'o lay. Wires d 27, contacts 28 and 29 of signals 2, and 1,;respectively, closed only when these signals are at stop, to the ctherterminal and-(2,) beginning at the terminal (+3, 'back'contact @176 .oftrack relay T. wire 18. Windin OI, fl elav'L, wires 19 and and contacts Z8Yand 29, to the other terminal The stick circuit for this relay L may be traced as followsgebeginning at the terminal front contactlfi of relay heating coil 38 of relay TR, stick contact 39 of relay'L, wire 18, winding of relay L', "wires 19 an'dZiQcontacts 28 and 29 to the other terminal It will-be noted that the heating coil 38 is normally included in the energizing stick circuit for the relay the current in this circuit is too small to cause mu h hes t nn- If ne oi the signals should lie e m-tard l ared the relay L would si p.

and upon return of the signal to stop the heating coil 38 will be connected directly across the terminals and through the back contact 39 of relay L and after a time, preferably two' minutes, will heat the bi-metallic metal of relay TR sufiiciently to close contacts 17. It should also be noted that the relay L can be picked up without the lapse of time if the detectortra'ck circuit becomes occupied while both signals are at stop, namely through back contact 16 of detector track relay T and wires 18 and 19. .These features afford protection against operating the switch machine under dangerous traffic COIIdi-e tions. As conventionally shown, the switch machine SM may be operated to its normal position through the normal wire N'when the control re-' lay Z assumes its normal position through the medium of the contact 10 of this control relay Z, providing of course that the lock relay L is energized, as is required by the front contact 11 of the lock relay L and that the detector track section is unoccupied, as required by contact66 of track relay T. This control relay Z is a polar neutral relay andis controlled from the interlocking office DO, through the medium of snap acting contacts 14 and'l5 of a switchlmachine lever SML, and has included in series therewith one of two windings of an indicating relay IR, all in a manner as more specifically pointed out hereinafter.

The relay WP is a switch machine repeater relay, but also serves as a'correspondence relay, in that this relay WP will be energized torthe position corresponding to that of the switch machine SM only in the event thatthe switch ma.- chine is in correspondence with the controlrelay Z. This switch machine relay WP is normally energized through the following circuitz beginning at the terminal of asuitable sourcelof current, contact 20 of the control 1'elay"Z,wire 21, switch machine'contact 22 (nosed only when the switch machine SM is in its-normal position, wire 23, winding of the relay WP, wire 24, switch machine contact 25, to the other terminal "of said source. -When the switch machine SM' and the controlrelay Z assumes the reverse dotted position the relay WP will be energized by a current of reverse polarity through a similar circuit readily traced in thedrawing and including the Wire 26 connecting the contact 20 of relay Z and a contact of the switch machine SM insteadof wire2l. 5 Y i f The correspondence relay CR'may be picked up onlyif the switch machine lever SML and the switch machine repeater relay WP assumecorresponding positions. The normal ,pick-up circuit for this correspondence relay CRJ'is shown closed in the drawing and may be traced as.follows,:' beginning at the terminal of suitable source, contact 30 of the lever -SML, ,wireBl, contact 32 of the relay WP, wires 33and 34', winding of the correspondence relay CR tothe other terminal A similar 'pick upficircuit for theflcorree spondence relay CR is intact "when, thefswitch machine lever SML and the switch machine relay WP assume the dotted position, in Which'case the wire 35 is included instead of the wire 31, it beingapparent that both of these circuits are open when the lever SML is out ofcorrespondence with'the relay-WP, Attention is directedto'the fact that the'corres'pondenc'e:relayiCR directly controls the signal relays SR and SR and fur* thermore that front contacts 36 and 37 01: relays SR and sRfirespectively, may energizethe core respondence relay CR, so that these'co-ntac't's '36 and 37 really constitute stick contacts for the correspondence relay CR, this because the relays SR or SR can only be energized after the correspondence relay CR has first been picked up. There are also associated with the lever SML three indicating lamps designated by reference characters signifying a flock-out-indicator L0, a transit light TL and a correspondence light CL. 'In order to more clearly dis'close the various features of the present system the operation thereof will be briefly pointed out.

common return wireC connected. to the. mid.-

point of said battery. This circuit maintains the control relay Z in its right-hand energized position, thereby closing at one point the normal circult including the normal'wire N for the switch machine SM, heretofore traced, thiscircuitof course being open within the'switch machine through the medium of contacts open only, when the switch machine assumes its full normal fDOsijtion; 'l' With the switch machine SM and the control relay Z assuming corresponding positions, the switch machine repeater relay WPwill be ener gized through the circuit heretofore traced was right-hand normal position. v

Let us now assume that it is desired to clear the signal l'to allow the movement of east-bound traflic on the maintrack, and that the operator moves his signal lever SL to clear the signal 1. Such mov'ement'ofthe lever SL closes the following circuit for the signal relay SR beginning at'the terminal (-1-) of a suitable battery, con tactof the lever SL wire '50, polar contact 51 of therelay 'WP assuming its right-hand posis tion,wir e"52, front contact 53 of the correspond ence relay CR, wire 54, winding ofthe relay SR}, to'the other terminal of said battery. The closure of thiscircu'it of course effects energiza tion of the signal relaySR and allows clearing of the signal 1 through its contact 64 and clear ing wire cl, providing of course that the switch machine SM assumes the main track position as manifested by the closureof contact 55 of the switch machine SM, and providingthat theho'me relay H is energized toward the right as manifested by the closure of itscontacts 55 and 59 to the right. When the home relay'H is energized to its reverse dotted position the signal 1 or '2, as

the case may be is energized to the cautionposiand 34, winding of the relay CR, to the other terminal It is apparent that if the operator were tomo e the switch machine lever SML at a timewhen'the lock relay L is deenergized,

its

as wouldbe the case with thesignal 1 clearythat suchoperationof the switch machine lever SML would not affect the control relay Z, this because the control relay Z is energized under these condi-' tions through the following stick circuit :+beginning at the terminal of a-suitable battery,

.pola-r contact 0f the relay vill, wire 61,, neutral oontact 62 of the relay Z,,wire,63,;baok;ooI-1taot48 of the relay L, wire 49,, winding of the relay Z,

through the common return wire 1C connected to the mid-point of such battery. Not only would such operation of the switch machine :lever under, the conditions assumed, not 'efiectlopemtion :ofthe switch machine SM, but furthermore such operation of the clever SML could not effect deenergization :of .the correspondence relay in spite of the ,f act that contact 30 of lever SMLis .now out 0f correspondence :with the (contact 32 of the relay WP, the correspondencerelay CR now being stuck up through the stick circuit heretofore traced including the .front contact 36 of j energized, this because the signal -1 has been cleared and has effected deenergization of this look relay L, such dropping of the :lock relay L will e-ifect deenergization of the indicating relay IR thus closing the back con-tact '65 of theindieating relay IR and lighting thelook-out lamp .Also, movement of the lever SML .to-zthe dotted position at this time will resultin this :lever being moved out of correspondence with the relay WP at a time when the indicating relay .IR is deenergized and its contact 43 is assuming the retracted position, from which it is apparent that picking up of the lock relay L thereafter will not result in picking up of the indicating relay IR, this because the circuit leading from contact 135 of thelever SML is not connected to a :sounceo'f energy, it now assuming the dotted position, and the circuit leading from thewcontaot .14 of the lever SML is open at the stick contact 43 of the indicating relay IR, so that even the subsequent energization of the lock relay L will :not result in the completion of the control circuit for the relay Z. In other words, movement of the lever SML at a time when the switch machine is looked against movement will not result in the subsequent control of. the switch machine or its control relay Z, and the operator will be required to return his lever SML to a position corresponding to that of the switch machine after. the lockreiay L is again energized in order to again energize the control relayZ, this control relay Z being deenergized its stick circuit opening as, soon. as the lock relay L picks up. Y Let us now assume that the lock relayL energized and the operator moves the lever'SML to the dotted position, under this condition the snap action contacts 14 and 15 of the lever SML very quickly move to their dotted position, they are in fact moved so quickly that the indicating relay IR has not had sufiicient time to open-its contact 43, so that the indicating relay IR'fland the control relay Z are now energized in series through the following circuit:-beginning at the terminal contact 14 of the .leverSML- wire 67, upper winding of the relay IR, wires 41 and 42, stick contact 43 of the indicating relay IR, wires 44 and 45, contact 46 of the relay WP, wire 47, front contact 48 of the relay L, wire 49, winding of the control relay Z, to the common return wire C connected to the mid-point of said battery. The two windings of the relay IR are so wound MP MIXES doctted position, so that the istick oon tact 43 ismo alongerrinoluded the energizing circuit for the control relay. Z. 11-, 1810f course understood that as S'OOILfl-S ithe mtrol relay 2 has :heenaperatedv to its 'dotted position (the energiz'ingcircuit for the switch-mas chine repeater relay WP is :broken at the contact 1-0, of rthfiil'GlBU therebyefiecting droppingxo'f jth'emeutral cont-act 70,01 the relay WP an-dil- .-lumination of the transit :light TLl, this transit light TL heing extinguished as-gs'oon as thezswitoh SM has been operated in correspondonce with the-controlrelay Also, since the signal :levers SL and "SL were assumed to be in their normal stop position when the switch .m-arlohzizne =SM was it s ,reverse';position, the correspondenoeirelay CR was deenerg-ized during interim at operation of t-he switch machine lever its contact 30 and the operation-oi the contact 32 of the relay ,WR, so that the corre- .spondence relay CR illuminated the out et-cor- 3 respondence light CL duringfthis period, through the medium of the contact -='71 of the relay-CR;

In the sa-me'inannerlas already explained-in connection with the signalrelay SR}, the signal relay SR cannot be energizedunlessthecontact T12 of the switch machine ltepeaterrelay WP assumes its take -siding dotted position, the signal leverTSL assumes its lclear position and the con.- respondencerelay CR -assu 'nes its energized position as mani-iested by the. contact 573 or the relay CB, and with the signal relay SR nce energized the correspondence relay GR is thenstuck up through front contact 37 of relay SR Applicant has thus provided 'asystem in which the switch mach-finecannotbe operated unless I" theswitch imach'ine control lever .SML is operated at a time when the switch is unlocked, namely when the .lock relay, L is energized, that a signal cannot be cleared .uhlesstheswitch machine lever correspondence with the switch machine, and a signal once clear the placing of the switch machine lever out of correspondence with the switch machine will not result in the movement of a signal to thestop position, this because correspondenceof the switch machine with its control lever is necessary during the process of clearing the signal and is not necessary after the signal has been cleared. I,

Having. shown and described one rather too s'i'leciitic embodiment of the present invention, it

is desired 'to' .be understood that the particular circuit arrangement illustrated has been selected as an enemplification of the invention and has not been selected for the purpose of showing the I scope of the invention nor the exact construction preferably employed in practicing the invention, but has been selected to Iacilitate describing the n rlvms p nci s -i ve on i s mod of operation and the novel -zfunctions -'--accofiiplisbed thereby, and that various changes, modificationsand additions, maybe made to adapt-the invention to the particular problem encountered in practicing the, same, "without Qdepartirig from the spiritmiQpe of the invention except as ee b th sw ped t iell win ji' aimjs present invention which are improvements over the disclosures of the above named applications.

What I claim as new is:

-' 1. In a system for electrically interlocking railway 'trafiic controllingidevices, fa track switch operated by-a switch machine, signals govern,-

ingtrafiic over saidtrack switch; acontrolrelay for controlling 'said'switch machine, a lever for controlling said control relay, contacts operated bysaid switch machine, a switch repeater relay arranged to indicate-the correspondenceof the position of said contacts with the position of said switch machine control relay, a correspondence relay initially energized only when said'switch repeater-relay and saidcon trol lever for controlling said control relay assume corresponding -'-positions, signal control-relays havingenergizing circuits including contacts on said switch repeater relay and contactson said correspondence relay, and a circuit'organization for said correspondence relay including a [front contact fon each-of said signal" control relays in multiple,

whereby the control of said signals is subject to the correspondence of sai'd switch-control lever and said switch repeater' relay only when said signal-'control relays are-deenergized. 1 Q 2. In a system forelectricallyinterlocking railway traffic controlling devices, a" track switch operated by aswitch' machine, signals governing traflic over said track" switch, a control circuit for'said switch machine including contacts of a control'leverj lockout means for'preventingthe control of 'saidswitch machine through said control circuit, a correspondence relay energized in accordance with the correspondence or said switch machine and its control lever, control relaysfor said signals, energizing circuits for said signal control-relays including contactslof said correspondence relay, and a second energizing circuit for said correspondence relay including a'contact of one of said signal c'ontrol relays'. "3. In a system for electricallyinterlocking railway "-trafiic controlling devices, a'track switch operated by a switch machine, signals governing trafilc over said track switch, a control-relay for said switch machine, a manually operable lever controlling saidswitch machine control relay, lockout'means for preventing thecontrol of said switch machine control relay, a'switch repeater relay arranged to check'the correspondence of said switch machine and said'switch' machine control relay, a correspondence 'relay arranged to check the correspondence" of said switch repeatingrelay and said switch control lever, 'signal control relays for said signals having ener-' gizing' circuits which include contacts on'jsaid switchrepeater relay and contacts on said corre-, spondencerelay, and a stick circuit for said correspondence relay including contacts of -oneof said signal control relays.

4. In combination, railway-system including a track switch, a switch machine for operating .said track switch] a lever for controlling-{said switchmachine, lock-out relay for when deenergized preventingcontrol of said switch machine in-response to a change in the position of said lever, a correspondence relay initially energizable only when-said lever and said switch machine assume corresponding positions, a signal for governing traffic over said track switch which signal must be at stop to energizesaid lock -out relay, a signal device which must be energized to cause said signal to display a proceed indication, a circuit for energizing saidsignal device including a front contact of said correspondence relay, and a' second circuit for said correspondence relay including a contact of said signal-device closed only when said signal device is energized, whereby correspondence between said lever and switch machine is necessary only during the act of clearing of said signal.

5. In combination, a track switch, a switch machine for operating said track switch, a control leverhaving a snap-action contact for controlling said switch machine, a signal for governingmovement of traffic over said track switch, a clearing circuit for said-signal which'may be closed only if said track switch and saidcontrol leverassume corresponding positions but which if closed will remain closed independently of correspondence of said switch machine and said control lever, and means for indicating'when said switch machine'ass'umes an extreme position but out of correspondence with said control lever.

6. In combination, a track switch (S), a switch machine (SM) for operating said track switch (S), a lever (SML) for governing the operation of saidswitch machine (SM), a switch position repeating relay (WP), a correspondence relay (OR), a pick-up circuit (33) for said correspond-- 'ence relay closed only when said lever (SML) and said switch position repeating relay (WP) assume corresponding positions, a signal (1) governing traflic over said track switch (S), a signal control relay (SR for said signal, circuit means for clearing said signal (1) when its control relay (SR is energized, manually'o'perated means (SL for energizing said control relay (SR only when said correspondence relay (CR) is energized, and a circuit (58) for said correspondence relay (CR) including a contact (36) of said signal control relay (SR '7. In combination, a track switch, a switch machine for operating said track switch, a lever for governing the operation of said track switch, a switch position repeating relay, a correspond- 'ence relay, a pick-up circuit forsaidcorrespondence relay closed only when said lever and said switch position repeating relay assume corresponding positions, a'plurality of signals governing traflic over said track switch, a signal control relay'for each of said signals, control circuits for each of said signals including a front contact of its corresponding'signal control relay, an energizing circuit for each of said signal control relays including a front contact of said correspondence relay, and a holding circuit for said correspondence relay including a front contact of any one of said signal control relays.

8; In combination, a track switch, a switch machine for operating said track switch, a lever for governing the' operation of said switch machine, a switch position repeating relay, a correspondence relay, a; pick-up circuit for said correspondence relay closed only when said lever and said switch position repeating relay assume corresponding positions, a plurality of signals governing traflic over said track switch, a signal control relay for each of said signals, control circuits for each of said signalsincluding a front contact of its corresponding signal control relay,

an energizing circuit for each of said signal control relays including a front contact of said correspondence relay, a holding circuit for said correspondence relay including a front contact of any one of said signal control relays, and means for automatically opening said energizing circuit for that signal which is cleared upon the passage of a train to thereby put that signal to stop independently of its corresponding signal control relay, whereby the passage of the train does not open the holding circuit of said correspondence relay.

9. In combination, a control lever for governing a power operated track switch, a switch position repeating relay governed in accordance with the power operated track switch, a correspondence relay, a pick-up circuit for said correspondence relay closed only when said control lever and said switch position repeating relay are in corresponding positions, signals for governing traflic over said track switch, manually controlled means for clearing said signals, stick circuit means for maintaining said correspondence relay energized independently of the correspondence between said control lever and said switch position repeating relay whenever said manually controlled means is in condition to clear any of said signals, means for causing any clear signal to automatically assume a stop condition upon the passage of a train independently of said manually controlled means and without rendering said stick circuit means ineffective, whereby such signal being automatically put to stop will automatically clear when the train has passed if its corresponding manually controlled means is still in a clearing condition.

SEDGWICK N. WIGHT. 

